New deterministic cascade layer (CascadeLayer::RoadGraph) building the
transport topology between Layer-3 settlement placements, stored on
BodyWorldState.road_graph (session-cached, never serialized).
- MST force-connect (strict Kruskal over squared distance) + secondary
links across a 30-60% body-scale band where the MST detours >1.5x.
- A* over the Layer-1 terrain-cost field on a coarse ~64-wide routing grid:
ocean/lake impassable, river corridors 1/2 cost, slope >=35deg (D-210
roughness ~0.7) 10x, else the D-210 terrain_modification_cost. Columns
wrap (equirectangular); integer costs + index tie-break keep A*
deterministic.
- MaintenanceAuthority per edge (new generator.rs enum) from endpoint
political archetypes + haul length; waypoint nodes at long-edge midpoints;
named-route identity join (designed-for, pool empty post-D-223); junction
detection (high_connectivity_junctions, degree>=3).
Wired into the cascade (gen_queue requests CascadeLayer::RoadGraph). Adds
Copy to PoliticalArchetype. 10 road_graph unit tests + a cascade e2e test;
full suite + clippy --all-targets -D warnings green.
Deferred to T-1076 (gated on the D-242 settlement model): the RailHeadFacing
junction pass (needs a D-213 FoundingOrientation amendment + Layer-4 handling)
and the hub-selection refinement (needs baked population/specialization).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
jpmschweitzerandClaude Opus 4.8
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